Housing for electrical components

ABSTRACT

A housing for electrical components is provided. The housing may include a mouth portion to cooperate with a circuit board in an assembled condition wherein said circuit board is applied against said mouth portion of the housing. The housing may include at least one spring formation located at said mouth portion to cooperate with said circuit board to elastically urge said circuit board away from said mouth portion, and at least one hook-like formation extending from said mouth portion distally of said housing, said hook-like formation adapted to cooperate with said circuit board to retain said circuit board assembled to said housing against the force exerted by said spring formation.

FIELD OF THE INVENTION

This disclosure relates to housings for electrical components, and wasdeveloped with specific attention paid to its possible use in providinghousings for high-power LED lighting applications.

However, reference to this exemplary field of application is not to beconstrued in a limiting sense of this disclosure.

DESCRIPTION OF THE RELATED ART

Housings for electrical components may include a cup-like or tray-likebody including a mouth portion intended to cooperate with a circuitboard (such as e.g. a printed circuit board or PCB). In a mountedcondition, the circuit board may be applied against the mouth portion ofthe housing so that the housing may cover and protect the electricalcomponents mounted on the circuit board.

Housings of the type considered in the foregoing may require a largenumber of multi-interactive components, with complex mechanicalconnections and additional fixing components such as e.g. screws,gluing, and so on. These arrangements almost inevitably result in ratherbulky and complex solutions, which are not desirable e.g. for LED lightsources.

OBJECT AND SUMMARY OF THE INVENTION

The need is therefore felt for housing arrangements adapted forintegrating a housing system structure while at the same time providing:

-   -   a stable mounting structure,    -   easy adjustment to tolerances in the parts being assembled,    -   integration between the elements assembled (also taking into        account the different nature of these components e.g.        electronics, optical, components producing thermal dissipation),    -   easy assembly/disassembly of the housing.

The object of the invention is to provide a fully satisfactory responseto that need.

According to the present invention, that need is met by means of ahousing for electrical components having the features set forth in theclaims that follow.

The claims are an integral part of the disclosure of the invention asprovided herein.

In an embodiment, such a housing includes:

-   -   at least one spring formation located at the mouth portion of        the housing to cooperate with the circuit board to elastically        urge the circuit board away from the mouth portion of the        housing, and    -   at least one hook-like formation extending from the mouth        portion distally of (i.e. away from) the housing; the hook-like        formation is adapted to cooperate (directly or indirectly, with        the possible interposition of an additional element such as e.g.        a heat-sink) with the circuit board to act as a hook to retain        the circuit board assembled to the housing against the force        exerted by the spring formation.

In an embodiment, the hook-like formation provides a primary snap-insystem providing a sandwich-like assembly while the circuit board issandwiched between the housing and another component such as e.g. aheat-sink.

In an embodiment, the spring formation forms an integrated spring systemfor absorbing tolerances in the assembled part, possibly ensuring e.g.automatic optical centering of LED lighting system elements.

In an embodiment, a secondary snap-in element is included providing botha mechanical action (i.e. assembling parts) and a fluid-dynamic action(i.e. forming channels for cooling air flow).

In an embodiment, cylindrical concave elements are provided to permiteasy integration with a cooling fan as well as fixing of the housing.

Embodiments of the invention provide improved performance over the priorart in terms of:

-   -   mechanical stability,    -   compactness,    -   assembly flexibility in terms of absorbing tolerances in the        parts being mounted/assembled;    -   a multi-functional fixing structure,    -   a fixing arrangement which is not visible from outside,    -   avoiding additional fixing elements, and    -   a simpler manufacturing process and improved quality assurance.

BRIEF DESCRIPTION OF THE ANNEXED FIGURES

The invention will now be described, by way of example only, withreference to the annexed figures of drawing, wherein:

FIG. 1 is a general perspective view of a housing for electricalcomponents as described herein;

FIG. 2 is representative of a condition of use of the housing of FIG. 1;

FIG. 3 is a cross-sectional view of certain elements shown in FIG. 2;

FIG. 4 is representative of the geometrical features of one of theelements shown in FIGS. 1 to 3; and

FIGS. 5 and 6 detail further features of the housing described herein.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the following description, numerous specific details are given toprovide a thorough understanding of embodiments. The embodiments can bepracticed without one or more of the specific details, or with othermethods, components, materials, etc. In other instances, well-knownstructures, materials, or operations are not shown or described indetail to avoid obscuring aspects of the embodiments.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment may beincluded in at least one embodiment. Thus, the appearances of thephrases “in one embodiment” or “in an embodiment” in various placesthroughout this specification are not necessarily all referring to thesame embodiment. Furthermore, the particular features, structures, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

In FIG. 1, reference numeral 10 denotes as a whole a housing forelectrical components.

In an embodiment, the housing 10 is comprised of a single body of amoulded material, such as plastics material.

In the exemplary embodiment shown, the housing 10 is essentiallycomprised of a body of an inverted-vat shape (i.e. a cup-like ortray-like shape) to define a reception volume for electrical components(e.g. electronic or photo-electronic components such as one or more LEDlight sources) which may be mounted—in a manner known per se—on acircuit board such as a printed circuit board or PCB 12.

For the sake of simplicity of illustration, the circuit board 12 isrepresented only in FIGS. 2 to 4.

In the assembled condition of the housing 10, the printed circuit board12 is applied against the mouth portion 14 of the housing 10 in order toform a sort of a box. In an embodiment, the components mounted on theupper side of the printed circuit board 12 extend into the internalcavity of the “box” formed by the housing 10.

In the exemplary embodiment shown, the housing 10 has a parallelepipedshape overall and the mouth portion 14 is thus of a rectangular shape.Those of skill in the art will appreciate that such a general shape ofthe housing 10 and the mouth portion 14 thereof is in no way mandatory.Other embodiments may include e.g. a housing 10 which has e.g. acylindrical, hemispherical, ovoidal shape (this list being in no wayexhaustive) and the mouth portion 14 may present a shape which is e.g.round, polygonal, lobe-shaped (this list being again in no wayexhaustive).

The housing 10 may be closed at its bottom or apertured e.g. includeonly a peripheral wall and/or be only partly closed at the bottomportion of the cup-shape: in FIG. 6 an embodiment is shown where thebottom wall of the housing 10 is provided with apertures in the form ofarched slits to provide passageways for cooling air as propelled by acooling fan.

In the exemplary embodiment shown, the mouth portion 14 is defined by aflange at least partly outwardly protruding from the peripheral wall ofthe housing 10. Such a flange 14 may be provided with openings 16(visible both in FIG. 2 and in FIG. 5) that bestow on the flange 10 asort of grill-like appearance.

In the embodiment to which FIGS. 2 and 3 refer, the printed circuitboard 12 is a flat board applied against the mouth portion 14 of thehousing 10 as the intermediate element of a sandwich-like arrangementalso including a further component such as a heat-sink providing thermaldissipation for the components mounted on the printed circuit board 12.

Such an additional component as the heat-sink 18 may include:

-   -   a flat web portion adapted to lie against the face of the        circuit board 12, and    -   fins or other protrusions 18 a extending from the web portion        away from the housing 10 (i.e. distally of the housing 10 in the        final assembled position).

As better appreciated in FIGS. 2 and 3, the sandwich-like arrangementreferred to in the foregoing will thus include the housing 10 and theheat-sink 18 having the printed circuit board 12 sandwiched therebetweenat the mouth portion 14 of the housing 10.

Distributed along the periphery of the mouth portion 14 are a pluralityof locking assemblies 20.

In the exemplary embodiment shown herein, four locking assemblies 20 arearranged at each of the four sides of the mouth portion 14 of thehousing 10.

In the exemplary embodiment shown, each locking assembly 20 is locatedat least slightly off-centre the respective side of the mouth portion14, the various locking assemblies 20 being otherwise almost uniformlydistributed over the whole development of the mouth portion 14.

While a plurality of such locking assemblies 20 are shown, those ofskill in the art will appreciate that the presence of a plurality ofsuch assemblies is not mandatory, since just one locking assembly 20 maywell serve the purposes herein.

The or each assembly 20 is comprised of at least two elements thatensure proper assembly of the printed circuit board 12 (and possibly theheat-sink 18) against the mouth portion 14 of the housing 10. A thirdelement may be optionally present as better detailed in the following.

The first element in the locking assembly 20 is a tongue-like springelement 201 having the overall shape shown in greater detail in FIG. 4.In an embodiment, the spring or springs 201 is/are integrally mouldedwith the housing 10.

Specifically, FIG. 4 shows the geometrical characteristics of anexemplary spring element 201 extending cantilever-like from the mouthportion 14 of the housing 10. These geometric features will be detailedin the following.

Essentially, the role of the (each) spring 201 may be to cooperate withthe periphery of the printed circuit board 12 in order to elasticallyurge the circuit board 12 away from the mouth portion 14 of the housing10. Stated otherwise, as the board 12 (possibly associated with theheat-sink 18) is placed against the mouth portion 14 of the housing 10,the spring or springs 201 will elastically deform under the pressureexerted by the board 12 and thus exert a contrary reaction force whichwill tend to “push” the board 12 (and the heat-sink 18) away from themouth portion 14 of the housing 10.

The complete displacement of the board 12 (and the heat-sink 18) awayfrom the mouth portion 14 of the housing 10, with the ensuing risk ofseparation from the housing 10, is prevented by the hook-like actionexerted by the second element 202 included in the (or each) lockingassembly 20.

In an embodiment, the hook-like element or elements 202 is/areintegrally moulded with the housing 10.

As indicated, the spring or springs 201 will tend to push the board 12and the heat-sink 18 away from the housing 10. The hook-like formationor formations 202 has/have a distal hook portion projecting at leastslightly radially inwardly of the housing and thus adapted to snap-inengage with the board 12 and/or the flat web portion of the heat-sink 18as better shown in FIG. 3 in order to prevent (“lock”) the movement ofthe board 12 and the heat-sink 10 away from the housing 10.

In an embodiment, co-operation of the hook-like formation or formations202 with the periphery of the board 12 and the flat web portion of theheat-sink 18 is a “snap-in” cooperation due to an elastically resilientnature of the hook-like formations 202.

During an exemplary assembly step with the housing 10, the board 12(having the components mounted thereon) and the heat-sink 18 areadvanced towards the mouth portion 14 of the housing 10. Due to theflexible nature of the element or elements 202, the hook (i.e. “head”)portions of the element(s) 202, which at least slightly protruderadially inwardly of the housing 10, will slightly spread open asschematically shown in FIG. 3 and thus permit the board 12 to be broughtinto abutment against the mouth portion 14 of the housing 10.

The length of the elements 202 may be defined as a function of thethickness of the board 12 and of the web portion of the heat-sink 18 insuch a way to permit the hook portion of the or each element 202 tosnap-in engage “behind” the web portion of the heat-sink 18 as shown infull line in FIG. 13 so that the board 12 and the heat-sink 18 will beanchored against the mouth portion 14 of the housing 10.

In those embodiments where the presence of the heat-sink 18 (or anyother similar component to be associated with the board 12) is notenvisaged, the length of the elements 202 may be defined as a functionof the thickness of the board 12 (alone) in such a way to permit thehook portion of the or each element 202 to snap-in engage “behind” theboard 12 so that the board 12 will be anchored against the mouth portion14 of the housing 10.

Similarly, while abutment against the mouth portion 14 of the housing 10has been referred to in the foregoing for the sake of simplicity,observation of FIG. 4 shows that the board 12 will not exactly abutagainst the mouth portion 14 of the housing 10 but rather against thespring or springs 201 extending therefrom.

The elastic coupling thus achieved will absorb any tolerances (includingthe board 12 being possibly slightly warped) while providing a stronganchoring force (e.g. 2N minimum) largely sufficient to bestow therequired stability on the sandwich structure comprised of the housing 10and the heat-sink 18 having the board 12 sandwiched therebetween.

As better detailed in FIG. 4, in an embodiment, the spring 201 is in theform of a L-shaped cantilever spring element including a proximalportion extending from the mouth portion 14 approximately orthogonalthereto and a distal portion or “arm” 2010 extending approximatelyparallel (in fact, at an angle φ) to the mouth portion 14 of the housing10 and terminating with an outwardly protruding spherical or cylindricalhead 2012 adapted to cooperate with the board 12.

In FIG. 4, X denotes the length of the arm 2010 while φ denotes thedeformation angle formed by the arm 2010 with respect to the directionof the plane of the mouth portion 14 of the housing 10.

Y_(h) denotes the interference between the compressed components (thatis the board 12 and the web portion of the heat-sink 18 which arecompressed between the head 2012 of the spring 201 and the distal hookportion of the element 202) in terms of punctual pressure.

Y_(h) can be generally written as:Y _(h) =f(X,φ,σ material)

where:

X=arm of the spring 201

φ=angle of deformation

σ=elastic deformation of the material comprising the spring.

According to the geometrical relationship Y_(h)=X·sin(φ), the spring arm(X) can be regulated by adjusting Y_(h) and φ. For instance thefollowing relationship can be defined:

$\quad\left\{ \begin{matrix}{X = {n \times Y_{h}}} \\{\phi = \left( {1^{{^\circ}},\ldots\mspace{14mu},45^{{^\circ}}} \right)}\end{matrix} \right.$

-   -   where typically n=(1, . . . , 6).

The value of Y_(h) is also correlated with the tolerance analysis of thecompressed components, as follows:

$\quad\left\{ \begin{matrix}{Y_{h} \geq {Th}_{\min} < {+ {\sum\limits_{i = 0}^{n}Y_{i,\min}}}} \\{Y_{h} \leq {\frac{1}{k}{\sum\limits_{i = 0}^{n}\left( {Y_{i} + y_{i}} \right)}}}\end{matrix} \right.$

where:

-   -   Y_(i) is the thickness of the i-th component,    -   y_(i) is the tolerance of the i-th component    -   Th_(min) is the minimum thickness related to the mechanical        material characteristic; a typical value for Th_(min) may be        between 100-3000 micron.

K is an a-dimensional factor related to the maximum admissible elasticelongation as follows:

$K \propto \frac{1}{ɛ_{x}} \propto \frac{1}{\sigma_{elastic}}$

where

ε_(x)=x direction elongation.

For instance, by referring to FIG. 4, the following spring parameterscan be selected:

$\quad\left\{ \begin{matrix}{Y_{h} = {{0.2 + y_{0\min}} = {0.45\mspace{14mu}{mm}}}} \\{{Y_{h} \leq {\frac{1}{3}{\sum\limits_{i = 0}^{1}\left( {Y_{i} + y_{i}} \right)}}} = {1.08\mspace{14mu}{mm}}}\end{matrix} \right.$

A value of Y_(h) of 0.5 millimeters may thus be selected.

In the drawings, reference numeral 203 denotes a further element whichmay be included in the or each locking assembly 20.

The element 203 is another hook-like formation having a hook-likeconfiguration complementary to the hook-like configuration of theelement 202. Stated otherwise, while the distal hook portion of theelement 202 protrudes radially inwardly of the housing 10 to snap-inengage the board 12 (and the heat-sink 18, if present), the element 203has a distal hook portion extending radially outwardly of the housing10. In an embodiment, the element 203 is integrally moulded with thehousing 10.

The element 203 may form an additional snap-in system to provide a clampposition for external components of the assembly such as additionalhousing part that includes and/or covers all above mentioned fixingstructures.

In the embodiment shown, the further hook-like element 203 is arrangedat the outer rim of the flange 14 comprising the mouth portion of thehousing 10 so as to extend in correspondence with the openings/apertures16 intended to form an airflow passages to facilitate cooling of thearrangement.

The “body” or “root” portion of the element 203 preferably exhibits achannel-like shape so that the proximal portion thereof located at theflange 14 is not obstructive of air flow through the apertures oropenings 16.

FIG. 6 is exemplary of the possibility of providing at one or more ofthe corners of the housing 10 thickened portions 22 having an axialthrough hole 24 extending therethrough. These holes 24 permit mountingfixing element such as screws to fix a fan to the housing 10 to completeassembly thereof.

Without prejudice to the underlying principle of the invention, thedetails and embodiments may vary, even significantly with respect towhat has been described herein without departing from the scope of theinvention as defined by the annexed claims.

The invention claimed is:
 1. A housing for electrical components, thehousing comprising: a mouth portion to cooperate with a circuit board inan assembled condition wherein said circuit board is applied againstsaid mouth portion of the housing, the housing comprising: at least onespring formation located at said mouth portion to cooperate with saidcircuit board to elastically urge said circuit board away from saidmouth portion, and at least one hook-like formation extending from saidmouth portion distally of said housing, said hook-like formation adaptedto cooperate with said circuit board to retain said circuit boardassembled to said housing against the force exerted by said springformation.
 2. The housing of claim 1, further comprising: a plurality oflocking assemblies, each assembly comprising one said spring formationand one said hook-like formation, said locking assemblies distributedover the periphery of said mouth portion.
 3. The housing of claim 1,wherein said at least one spring formation and said at least onehook-like formation are integrally formed with said housing.
 4. Thehousing of claim 1, wherein said at least one spring formation is in theform of a flexible cantilever beam.
 5. The housing of claim 1, whereinsaid at least one spring formation is an L-shaped formation.
 6. Thehousing of claim 1, wherein said at least one spring formation comprisesa distal head to cooperate with said circuit board.
 7. The housing ofclaim 1, for assembly with the circuit board having a given thickness,said circuit board coupled with a further element having a web portionhaving a respective thickness, wherein said at least one hook-likeformation has a length corresponding to the combined thickness of saidcircuit board and said web portion of said further element.
 8. Thehousing of claim 1, wherein said at least one hook-like formationincludes a distal hook portion projecting radially inwardly of thehousing.
 9. The housing of claim 1, further comprising: at least onefurther hook-like formation located at said mouth portion and having adistal hook formation projecting radially outwardly of said housing. 10.The housing of claim 9, further comprising: a flange defining said mouthportion of the housing, said flange provided with openings bestowing onsaid flange a grid-like structure forming passageways for cooling airand wherein said further hook-like formation has a channel-likestructure defining a flow path for said cooling air.
 11. The housing ofclaim 9, wherein said further hook-like formation is integrally formedwith said housing.
 12. The housing of claim 1, wherein said housingincludes thickened portions having openings for fixing screws extendingtherethrough.